Oscillating valve



June 26, 1962 J. J. PlPPENGER 3,040,768

OSCILLATING VALVE Filed Aug. 15, 1959 United States Patent 3,848,768 fifaClliLAThlG VALVE John J. Pippenger, Manchester, Mich, assiguor to Double A Products Company, lvranchester, Mich, a. corporation of Michigan Filed Aug. 13, 1959, Ser. No. 833,423 Claims. (Cl. 137'-330) The present invention relates to spool valves and particularly to a spool-type pilot valve oscillated in a manner to prevent sticking or binding.

As is well known in the art, will sometimes tend to stick or bind in a manner that makes the spool difiicult to shift. For certain applications, such as solenoid actuated pilot valves, if. the-spool should stick or bind it will frequently prevent the solenoid frorn shifting the spool. very undesirable, particularly in many applications where dependability of operation is of primary importance.

It is one object of'the present invention to provide a greatly simplified construction for oscillating or dithering a spool-type pilot valve to prevent sticking. or binding of the spool.

It is. another object of the invention to provide, a pilot valve wherein the ported sleeve in which the spool slides isoscillated at a high frequency to prevent sticking or binding of the. spool.

It is a still further object of the invention toprovide a spool-type pilot valvehaving an oscillated ported sleeve which is economical to manufacture, simple in construction, and effective in. operation.

Other objects and. features of novelty of the invention will be specifically pointed out or otherwise become apparent when referring, for a better understanding of the invention, to the following description taken in conjunction with the accompanying drawing, wherein an elevational view, partly broken away, of a pilot valve embodying features of the present invention is illustrated. mounted on a spool valve.

Referring to the drawing, a pilot valve 2 embodying features of the present invention is illustrated mounted directly on another valve 4 which may be, for example, a spool valve controlled by the pilotvalve 2. .The pilot valve 2 comprises a body 6 having a transverse. bore 8 extending therethrough with enlarged counterbores. 10 and 12 at each end' thereof, each of the counterbores also being countenbored as at 14 and 16.

A ported sleeve 18 is slidably sealed within the bore 8, and a spool 20 is slidably sealed within the ported sleeve 18 in a conventional manner. Bushings 22 and 24 are slidably disposed on projecting ends 26 and 28 of the spool, respectively, and are normally urged into abutting engagement with shoulders 30 on the inner ends of the counterbore 1t) and 12, respectively, by coiled springs 32 and 34 to center the spool in the position illustrated. The other end of each of the springs bearsagainst a flange 36 of bushings 38 and 40 slidably disposed in the counterbores 14 and 16.

Suitable electric solenoids 42 and 44 are mounted on the sides of the :body 6 and compress the flanges'36 of the bushings 38 and 40 inwardly against suitable O-rings 46 disposed within the counterbores 14 and 16 to provide a fluid-tight seal. Plungers 48 and 50 of the solenoids 42 and 44 project from the solenoids through the bushings 38 and 40 and abutting-1y engage the projecting ends 26 and 28 of the spool 20, the plungers 48 and 50 being slidably sealed within the bushings by suitable seal elements 52 and 54.

With this construction, it is apparent that when the solenoids '42 and 44 are not energized the springs 32 and 34 will normally center the spool 20 in the position illustrated in the drawing wherein passageways 56' and 58 in the spool of a spool valve Of course, such. sticking is 7 Patented June 26, 19.62

the. body 6 communicate. with annular grooves 6.0 and 62 inthe ported. sleeve 18 which, in turn, communicate with. the central aperture extending through the ported sleeve by means of-radial passageways 64 and 66, respectively,

\ in aconventional manner. Of course, depending. upon the position of the spool 2.0 relative to'the ported sleeve 18' the radial passageways 64. and 66..will communicate with the other'radial passageways. and annular grooves of the ported sleeve 18. and. other passageways in the valve body 6 (not shown.) in a conventional manner.

The. spool 20 is shifted to the right by the plunger 48 when the solenoid 42 is energized, and is shifted to the left by the plunger when the solenoid 4.4 is energized, the spool returning to the. neutral position illustrated when bothof the solenoids are deener-gized. When. the. spool 20 shifts in this manner, it, of course, controls the flow of fluid through the passageways. 56 and 58 and. thereby controls the flow of fluid through passageways 68 and 70 in the valve 4. Since the particular valve lv illustrated is a spool valve,.the passageways 68 and 70. can alternately introduce pressurized fluid to one of the. chambersadj'acent, one end of the, spool ofthe valve 4 and connect the other chamber to tank ina conventional manner to hydraulically shift the spool back and forth to control the flow ofpressurized fluid through the valve "4.

- The improvement .of the. present invention, is specifically directed tothe problem of eliminating the sticking of the spool 20 in the ported" sleeve 18. and accomplishes this in a very unique manner, namely, by oscillatingor ditheringthe ported sleeve 18 relative to the body 6. To accomplish this the ported. sleeve 18 is slidably sealed in the bore. 8,- as previously mentioned, rather than press fitted within the bore as is normally done in prior art valve constructions. The ported sleeve 18 is also made slightly shorter in length thanthe distance between: the adjacent faces. of the bushings 22 and 24 so that it can be oscile la-ted back and forth.

Sincethe ported sleeve is. being oscillated, rather than the spool itself, for example, it can be oscillated very simply and, effectively by a miniature electric motor 72 V mounted on a. cap 74 secured directly to the body 6.

. bushing The output shaft '76 of the miniature electric motor 72 has an adapter 78 suitably secured thereto, such, as by a set screw 80 or the like, and the adapter has a tongue 82, projecting downwardly therefrom into a groove 84 in the upper end of a shaft 86' rotatably journal'edin'a counterborel 88 in the body 6 by suitable bearings 98. A reduced end portion 92' of the pin-86 extends down wardly through and is rotatably sealed within 'a flanged 94 seated within the counter-bore 88 with the body thereof press fit into an aperture 96 in the body 6, the lower end of the aperture 96 communicating directly with the central bore 8 adjacent an annular groove 98 in the ported sleeve-18. An eccentric pin 1% projects downwardly from the lower end of the reduced end portion 92 of the shaft 86 into the annular groove 98 in a manner to oscillate the ported sleeve 18 back and forth in response to the rotation of the shaft 86 by the miniature electric motor 72.

It will be observed that the diameter of the eccentric pin 100 is slightly less than the width of the annular groove 98 so that the eccentric pin engages the right wall of the groove 98 as it shifts the ported sleeve 18 to the right, and will engage the left Wall of the annuof the eccentric pin with the left wall of the annular groove.

From the foregoing, it is apparent that the present invention provides ahighly advantageous, simple and economical construction for preventing sticking of thev spool 8 Within the ported sleeve 18. By oscillating or dithering the ported Sleeve as described, rather than attempting to dither the spool itself, for example, the mechanism required for transmitting the oscillating movement is greatly simplified since the ported sleeve is more accessible. Further, thepresent invention provides a specific mechanism for ditheringthe ported sleeve, namely the eccentric pin 100 projecting Within the annular groove 98 of the ported sleeve, which can be readily actuated by a conventional miniature electric motor in a very convenient and economical manner.

While it will be apparent that the embodiments of 'the invention herein disclosed are Well calculated to fulaperture of said ported 'sleeve, a shaft rotatably journaled in said body and having an eccentric pin on one end thereof projecting into one of said angular grooves 011 said ported sleeve, and -a mim'ature electric motor mounted on said body and having the output shaft thereof keyed to, the other end of said shaft for rotating the shaft to cause said eccentric pin to oscillate the ported sleeve relative to said body. r t 2. A spool valve comprising a body having a central bore therein, a ported sleeve having an annular groove in the outer Surface thereof slidably sealed within said bore, a spool slidably disposed within said ported sleeve, a shaft rotatably journaled in said body and having 'an eccentric pin on one end thereof projecting into said annular groove on said ported sleeve, andmeans for rotating said shaft to cause said eccentric pin to oscillate said ported sleeve relative to said body.

3. A spool valve comprising a body: having a'central bore therein, a ported sleeve having an annular groove in the outer surface thereof slidably sealed within said bore, a spool slidably disposed within said portedsleeve, a shaft rotatably journaled in said body, means for rotating said shaft, said shaft having an eccentric pin whose diameter is less than the width of said annular groove on said ported sleeve into which it projects so that the rotation of the eccentric pin rotates and shifts the ported sleeve in one direction and rotates and shifts the ported sleeve in the opposite direction during each complete revolution of the eccentric pin.

4. A spool valve comprising a body having a central bore therein, a ported sleeve slidably sealed within said bore, said sleeve having a central aperture extending therethrough and a plurality of angular grooves in the annular surface thereof with radially extending ports communicating said annular grooves with the central aperture, a spool slidably disposed within the central aperture of said ported sleeve, a shaft rotatably journaled in said body, a miniature electric motor mounted on said body and having the output shaft thereof keyed to the other end of said shaft, said shaft having an eccentric pin on one end thereof whose diameter is less than the width of said angular groove into which it projects so that the rotation of the eccentric pin rotates and reciprocates the ported sleeve in one direction and rotates and reciprccates the ported sleeve in the opposite direction duringeach complete revolution of the eccentric pin.

5. A spool valve comprising a body, means defining a central bore in said body, means defining an aperture in said body intersecting said central bore, a ported sleeve slidablysealed within said central bore, a spool slidably disposed Within said ported sleeve, a shaft rotatably journaled in said aperture, means for rotatingsaid shaft, means defining an annular groove .in said sleeve having a first wall and a second wall, and an eccentric pin on one end of said rotatable shaft projecting into said annula-r groove to alternatively engage said first and second walls of said annular groove, Said eccentric pin having an outside diameter less than the width of said annular groove to produce a rolling engagement between said eccentric pin and said first and second walls of said annular grooverfor concurrently rotating and reciprocating said ported sleeve within said central bore.

References Cited in the file of this patent UNITED STATES PATENTS 1,511,425 Rouc'ka Oct. 14, 1924 1,512,804 Roucka 0ct.'2l, 1924 2,065,702 Hubbard Dec. 29, 1936 2,426,986 Dawson Sept. 9, 1947 2,548,071 Saulsberry Apr. 10, 1951 FOREIGN PATENTS 691,383 Great Britain May 13, 1953 

